Electroretinograms from vitamin A deficient albino rats show a decrease in amplitude of the a and b waves as early as 27 days on the diet. This decrease continues as the duration on the deficient diet lengthens. Through two months on the deficient diet, the only correlation between the structural integrity of the retina and the reduction in amplitude is that the outer two-thirds of the outer segments lose their normal staining properties. Around four months, some outer segments show signs of deterioration; however, their inner segments appear normal. Light and electron microscopic studies of the retina, pigment epithelium and their interrelationship are in progress at various levels of deficiency.